3D visual representation of an organ assists a physician in assessing the condition of that organ. More particularly, a 3D representation of a tubular organ, such as a coronary vessel, helps identify and assess plaque burden and lesion dimensions such as length, diameter and volume. Further more, a 3D representation of a tubular organ aids the physician to identify, on a 2D image, regions of foreshortening of the vessel caused by the projection of the 3D vessel on a 2D plane. Additionally, with the aid of the 3D representation of the tubular organ, a physician can identify bifurcation points of that tubular organ.
U.S. Pat. No. 6,169,917, entitled “Method and Device for Reconstructing Three-Dimensional Images of Blood Vessels, Particularly coronary vessel, or Other Three-Dimensional Structure” to Masotti et al, directs to a method wherein three X-Ray images, from three different perspective are provided. A reference object, comprising two planes, integral with the patient, containing at least six points with known three-dimensional coordinates, opaque to the image radiation, provides the perspective transformations associated with each angiographic image. Using these transformations, and a set of points of projection of a three-dimensional object, the three-dimensional object is reconstructed.
The reconstruction is determined using a semi-automatic algorithm. Initially, a starting point and an initial direction of the vessel are determined. From thereon, the next segment of the vessel, whose length is proportional to the actual radius thereof, is identified. The segment is identified according to the probability that the vessel proceeds in a given direction. This probability is determined by calculating the mean gray level contained in a rectangular mask which is rotated about the point belonging to the center line of the vessel.
U.S. Pat. No. 6,148,095 entitled “Apparatus and Method for Determining Three-Dimensional Representation of Tortuous Vessel” to Prause et al, directs to an apparatus and method for reconstruction of the coronary vessel, generated from ECG-gated intravascular ultrasound (IVUS) frames obtained by a catheter, combined with biplane angiography. Initially, the IVUS catheter is positioned at the distal end-point of the designated vessel. The IVUS catheter is withdrawn at a fixed speed while biplane X-ray images are acquired. The IVUS catheter obtains ultrasound images from within the vessel during the withdrawal. Since either the catheter, or the lumen borders or both are present on the biplane X-ray images, a 3D representation of the centerline of the vessel can be reconstructed. Using this 3D centerline representation in conjunction with information about the physical properties of the catheter a 3D pullback path of the catheter is determined. The IVUS images are then mapped to the determined 3D pullback path according to the pullback speed and catheter twist. The gaps between adjacent IVUS slice are filled by interpolation. The IVUS images are further correlated with the activity phase of the heart. The activity phase of the heart is obtained by Electrocardiogram (ECG), to ensure that the images are obtained under consistent conditions.
U.S. Pat. No. 6,047,080 entitled “Method and Apparatus for Three-Dimensional Reconstruction of Coronary Vessel from Angiographic Image” to Chen et al, directs to a method for reconstruction of a 3D coronary arterial tree from routine biplane angiograms acquired at arbitrary angles and without using calibration objects. According to the method directed to by Chen et al, a plurality of 2D images of a target object is acquired. On each image, the centerlines of the vessels are identified. Using these centerlines, a vessel hierarchy data structure, including the identified 2D vessel centerlines is created. By traversing the corresponding vessel hierarchy data structure, a predetermined number of bifurcation points are calculated. Using the calculated bifurcations points, corresponding to each of the projected image, the rotation matrix and translation vector representing the relative orientation of the images are determined. Using these rotation matrix and translation vector, the correspondence between the 2D centerlines, corresponding to each image, is established and a 3D vessel centerline is calculated. A 3D visual representation, of the target object, is reconstructed based on the 3D vessel centerline and diameter of each vessel, estimated along the 3D centerline of each vessel. Consequently, the optimal views, of the vessel segments, with minimal vessel foreshortening, are determined.
U.S. Pat. No. 6,456,271 entitled “Vascular Reconstruction” to Reidfeld, directs to a method and apparatus for reconstructing blood vessels in three dimensions. A catheter, including a position sensor, is advanced into the blood vessel and the position of the sensor is acquired at a plurality of points in the vessel. Based on these points, a centerline and the inner surface of the blood vessel are calculated. The plurality of points is fitted to a parametric representation of the vessel centerline. Each coordinate dimension, in the parametric representation, is represented by a polynomial. The inner surface of the blood vessel is reconstructed about the centerline by generating a tube of either fixed or variable radius. This tube is generated by determining plurality of unit vectors, sampling the circle around the centerline, and multiplying these unit vectors by the radius of the tube. The radius is determined by averaging the distances of the points from the centerline. A reconstruction, with variable radius, is achieved by averaging the distances of a plurality of points in a vicinity of interest. Alternatively, the radius may be selected by the user. Using the centerline and the radius a wire frame of the blood vessel is generated and the rectangular patches composing the wire frame are shaded.